Effect of Underdamped Vibration on Excitation Energy Transfer: Direct Comparison between Two Different Partitioning Schemes
Journal
Journal of Physical Chemistry A ( J. Phys. Chem. A.)
Date
2019.03.20
Abstract
We study excitation energy transfer (EET) in a model three-site system with a mixed-quantum
classical dynamics method, by focusing on the effect of an underdamped vibration. We construct
two types of models where the underdamped vibration mode is included either in the quantum
subsystem or in the classical bath. We show that the two models yield practically equivalent results
despite the different depictions of the vibration. In particular, both models consistently
demonstrate accelerations of population relaxation induced by quasi-resonant vibration. This
indicates that intricate features of EET dynamics that have been frequently ascribed to the quantal
nature of vibrations, such as vibronic mixing, can be successfully reproduced by using physically
equivalent but classically described bath modes. The mechanism behind the observed quantumclassical
correspondence is proposed. We also systematically examine how the structure of the
spectating continuum phonon modes affect the vibronic resonance, and observe that phonon modes
with different timescales influence the resonance in different manners.